code: def _get_optional_parameters(self):
      return {"batch_size"}
  
imports: from bigdl.orca.automl.model.abstract import BaseModel, ModelBuilder
  import numpy
  from bigdl.orca.automl.metrics import Evaluator
  from bigdl.orca.common import SafePickle
  import copy
  import tensorflow
  from tensorflow.keras import backend
  import types
  from bigdl.dllib.utils.log4Error import *
label_desc: Use image node_id 13 for calling the KerasBaseModel obj's underlying member method code with example usage: obj._get_optional_parameters() and returns: unknown